The disruption comes just months before the Olympic Games, when China's leaders had hoped to display a 'harmonious society'. However, chaos has gripped Xiahe, which is home to a large community that considers itself part of greater Tibet even though it is outside of the Tibet Autonomous Region.

According to Sanjay Tashi of the Free Tibet Campaign, the city centre was filled with tear gas, cars were set on fire, government buildings ransacked and the banned Tibetan flag flew over a school.

Other witnesses said they saw 10 to 20 truckloads of riot police moving into the area. Police have fired tear gas rounds and arrested some protesters. But the crowd stormed the jail and released the prisoners, Tashi said.

In Lhasa, police have locked down the city, patrolling the streets and setting up checkpoints on many roads. Foreign tourists have been ordered to leave the central area, with many flying out of Tibet. Those who stay are restricted, though they say there has been no official curfew.

'The army and police forbid us from walking down the road, so our activity is confined to the hostel,' said one traveller. He said tanks and soldiers were patrolling the streets and guarding junctions. Other witnesses have reported troops setting up machine gun positions and there were unconfirmed reports of shooting.

The authorities blame Tibetan insurgents working on the orders of the Dalai Lama and have vowed to hunt down the perpetrators of what state media called 'sabotage'. Police warned that anyone who did not turn themselves in by Monday faced 'stern punishment by the law'.

...Overseas Tibetan groups say police killed at least 36 Tibetan protesters, including three monks. Free Tibet Campaign reports that 26 demonstrators were shot or blown up while demanding the release of political prisoners in Lhasa's notorious Drapchi prison. Other groups say the death toll could be more than 100.

The UN, US and UK have condemned Chinese repression - but not too loudly. After all, the Chinese hold all America's notes...and there's an Olympics coming. Wouldn't want to deprive the millions of their televised sport.